Motor-grader control system

ABSTRACT

Apparatus for control of double-articulated earth-working machinery of the type consisting of two similar mobile assemblies, including drive engine and traction elements, which are oriented in back-to-back manner to support a main frame therebetween. The control system of the earth-working apparatus enables automatic control of machine attitude relative to an external reference such as a string line, such automatic control being applied to generate continual steering regulation as well as continual correction of the height and level of the main frame which, in turn, carries the working implement therebeneath in earth engaging attitude.

United States Patent [72] Inventors George W. Swisher, Jr.

Oklahoma City; Don W. Smith, Edmond; Gordon L. Spivey, Oklahoma City;Ralph K. Snow, Oklahoma City, all of Okla.

[21] Appl. No. 812,229

[22] Filed Apr. 1, 1969 [45] Patented Oct. 5, 1971 [73] Assignee CMICorporation Oklahoma City, Okla.

[54] MOTOR-GRADER CONTROL SYSTEM 14 Claims, 14 Drawing Figs.

[52] U.S. Cl 172/4.5, 172/793 [51] Int. Cl 1102i 3/76, E02f 3/12 [50]Field of Search 172/45,

[5 6] References Cited UNITED STATES PATENTS 2,494,324 1/1950 Wright172/793 2,742,099 4/1956 Hagen 180/79.l 2,883,774 4/1959 Clifi'ord...37/1 17.5 X 3,122,850 3/1964 172/803 X 3,324,583 6/1967 172/7813,346,975 10/1967 37/129 X 3,346,976 10/1967 Curlett et al... 172/4.53,435,546 4/1969 lverson l72/4.5 X 3,468,391 9/1969 Rushing et a1.180/98 Primary Examiner-Robert E. Pulfrey Assistant Examiner-Stephen C.Pellegrino Att0rneyDunlap, Laney, Hessin and Dougherty ABSTRACT:Apparatus for control of double-articulated earth-working machinery ofthe type consisting of two similar mobile, assemblies, including driveengine and traction elements, which are oriented in back-to-back mannerto support a main frame therebetween. The control system of theearthworking apparatus enables automatic control of machine attituderelative to an external reference such as a string line, such automaticcontrol being applied to generate continual steering regulation as wellas continual correction of the height and level of the main frame which,in turn, carries the working implement therebeneath in earth engagingattitude.

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BACKGROUND OF THE INVENTION 3 1. Field of the Invention The inventionrelates generally to control apparatus or earth-working machinery and,more particularly, but not by way of limitation, it relates to improvedmotor-grader control systems having increased versatility ofapplication.

2. Description of the Prior Art The prior art includes the usual formsof control system as are employed in regulation of various functions inthe conventional types of motor-grader. That is, control systems for thesingle-articulated or single-ended motor-grader which has been theprimary design type. The prior types of control system were, ofnecessity, directed to regulation of an earthworking implement ascarried by a drawbar type of undercarriage. Prior types ofdouble-articulated earth-working machinery are exemplified by two priorU.S. Patents; a patent to Wright, U.S. Pat. No. 2,494,324, now expired;as well as a patent to Harris, U.S. Pat. No. 3,324,583. The controlsystems attendant these prior art structures are devices whichnecessarily include specific limitations characteristic of theirparticular structures, and the respective control system teachings donot extend into the realm of multiplanar and/or automatic controlrelative to an external reference, as is dealt with in the presentapplication.

SUMMARY OF THE INVENTION The present invention contemplates a controlsystem for a double-ended, double-articulated motor-grader assemblywhich includes a fully controllable main frame and working elements aswell as a movable operating cab. In a more limited aspect, the inventionconsists of first and second mobile assemblies each having a similardrive power source and mobile elements, and each supporting the oppositeend of a main frame which carries a subframe and working implement aswell as a rotatable operating cab. In addition, a system of electricallyactuated hydraulic powering elements enables highly accurate control ofsteering, main frame tilt, main frame slope control, and main frameelevation under either manual or automatic control as sensed from anexternal reference means.

Therefore, it is an object of the present invention to provide adouble-articulated motor-grader assembly which can be controlledautomatically from an external reference.

It is also an object of the invention to provide a motorgrader apparatuswhich has a greater degree of control over the main or middle frame and,therefore, a subframe and working implement affixed thereto.

It is still further an object of the present invention to provide adouble-articulated motor-grader which has a greater degree of steeringcontrol while guiding and controlling an earthworking implement.

Finally, it is an object of the present invention to provide a controlsystem for a motor-grader assembly which is readily employed in either amanual or automatic mode of operation.

Other objects and advantages of the invention will be evident from thefollowing detailed description when read in conjunction with theaccompanying drawings which illustrate the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side elevation of amotor-grader assembly constructed in accordance with the invention;

FIG. 2 is a top plan view of the motor-grader assembly as shown in FIG.I;

FIG. 3 is an enlarged elevation with parts shown in cutaway of a mobileassembly as constructed in accordance with the invention;

FIG. 4 is an enlarged top plan view of a mobile assembly of theinvention with parts shown in cutaway;

FIG. 5 is a section taken along lines 5-5 of FIG. 1;

FIG. 6 is an enlarged section as taken along lines 66 of FIG. 5;

FIG. 7 is an enlarged side elevation of the main frame of the inventionwith parts shown in cutaway;

FIG. 8 is a schematic diagram of the main frame tilt control assembly;

FIG. 9 is a schematic diagram of the subframe cross-slope controlassembly;

FIG. 10 is a schematic diagram of the steering control assemblyconstructed in accordance with the invention;

FIG. 11 is a schematic diagram of additional structure of the steeringcontrol assembly;

FIG. 12 is a schematic diagram of the main frame tilt control assemblyas constructed in accordance with the invention;

FIG. 13 is a top plan view of the motor-grader assembly includingcontrol sensor support assembly; and

FIG. 14 is a block diagram of control systems interconnections.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIGS. 1 and 2, amotor-grader assembly 10, consists of an A END mobile assembly 12 and anoppositely oriented B END mobile assembly 14 with a frame assembly 16pivotally supported therebetween. The A END and B END mobile assemblies12 and 14 respectively, may be identical units supported on tandem wheelassemblies and 18b bearing on rubber-tired wheels 20a and 20b,respectively. While motor-grader assembly 10 is shown as being supportedon pluralities of tandem arrayed rubber-tired wheels 20a and 2012, itshould be understood that various other forms of ground supportingmobile means such as traction units, single or plural wheel assemblies,etc., may be employed in the mobile ground supporting function.

Each of mobile assemblies 12 and 14 further consists of a chassis 22aand 22b supported atop tandem wheel assemblies 180 and 18b at a centralpoint (to be further described below) and a suitable power source orengine 24a and 24b is supported thereon. Prototype motor-grader unitsare presently designed to include 225 horsepower diesel engines of atype which is commercially available from the Caterpillar Tractor Co. ofPeoria, Ill. The engines 24a and 24b function with hydraulic pumps andmotors which are utilized for various power purposes about motor-graderassembly 10 as will be further described below. Hood cowls 26a and 26bare affixed over respective engines 24a and 24b in secure mannerrelative to chassis 22a and 22b while conventional bumper structure 28aand 28 b, exhaust stack 30a and 30b, and air cleaners 32a and 32b aresuitably adapted.

The main frame assembly 16 is pivotally supported on the A END mobileassembly 12 about a point indicated by vertical axis designation 34, andit is. supported at its other end by the B END mobile assembly 14 abouta vertical axis designation 36. The main frame assembly 16 consists of acentral frame 38 having each end extending into a downward curve, Le.central frame ends 40 and 46 formed in the downward extremity thereof.Central frame 38 has a mounting plate 48 securely atfixed as by weldingacross its upper, horizontal surface and a pair of bearing shafts 50 and52 are secured therethrough in parallel, transverse disposition to forma plurality of quadrature arrayed support shafts 54, 56, 58, and 60.Support shafts 54 and 60 extendoutward. in parallel, spaced andhorizontal disposition from one side of central frame 38 while supportshafts 56 and 58 extend in respective opposite dispositions on the otherside of central frame 38.

The end 40 of central frame 38 includes a pair of beams 62 and 64 (seeFIG. 2) and the other end 42 is similarly formed by a pair of taperingbeams 66 and 68. The support shafts 54, 56, 58 and 60 provide supportconnection for the central frame 38 as they are each pivotally affixedto respective arm ends 70, 72, 74 and 76 for movement about a transverseaxis.

The arm ends 70 and 72 form part of a bifurcated frame 78 while the arms74 and 76 form part of an oppositely disposed bifurcated frame 80. Eachof bifurcated ends 70, 72, 74 and 76 receives a semicircular bearingbracket 82, 84, 86 and 88 in secure aflixure for the purpose of movablyseizing each of the respective support shafts 54, 56, 58 and 60.

The opposite or outer ends of the respective bifurcated frames 78 and 80are each mounted to respective mobile assemblies 14 and 12 for pivotalaffixure about vertical axes 36 and 34. The hydraulic cylinder 90 isconnected within bifurcated frame 78 to extend a piston arm 92 intopivotal connection with pivot eye 46 of central frame end 42. Similarly,the hydraulic cylinder 94 is affixed upwardly within bifurcated frame 80to extend a piston rod end 96 downward into pivotal connection withpivot eye 44. Actuation of hydraulic cylinders 90 or 94 enable movementof the central frame 38 relative to each of the bifurcated frames 78 and80 which motion must necessarily extend through to effect counterbalanceat respective tandem assemblies 18b and 18a.

The mounting plate 48 of central frame 38 actually provides a smoothplate about which operating cab 100 is supported. The operating cab 100consisting of operators space 102 and having windshield area 104 issupported on one end of a support am 106 which, in turn, has its otherend pivotally affixed on mounting plate 48 for movement about a verticalaxis 108. The support arm 106 includes drive and braking mechanism, aswill be further described below, which operates in conjunction withmounting plate 48 to position the operators cab 100 in any desiredposition relative to main frame 16.

A subframe 110, exemplarily shown as being octagonal in construction, issupported beneath main frame 16 in laterally pivotal manner. Thus,subframe 110 is pivotally affixed at a first pivot assembly 112 which isrigidly secured beneath a crossmember 114 extending between frame arms62 and 64. Similarly, the opposite end of subframe 110 is pivotallyaffixed to a pivot assembly 116 which is secured beneath a crossmember(not shown), secured as by welding between the opposite bifurcated framearms 66 and 68. Pivotal or attitude control of subframe l 10 relative tomain frame 16 is exercised by control of a pair of hydraulic cylinder118 and 120, each of which is pivotally affixed to opposite sides ofcentral frame 38 to extend respective pistons 122 and 124 into asuitable pivotal connection at the opposite sides of the subframe 110. Apair of sensor support arms 119 and 121 extending respective telescopingrods 123 and 125 are securely affixed across opposite sides of subframe1 10 to extend transversely relative to motor-grader assembly 10.

The subframe 110 provides further movable support of a rotatable ringmember 126 which supports a working implement, e.g. a blade assembly128, therebeneath. Ring member 126 is supported for circular movementwithin a plurality of support blocks 130 beneath subframe 110, andsuitable drive means (as will be further described) are mounted onsubframe 110 to provide circular rotation of ring member 126. Theworking element, such as blade assembly 128, is secured beneath ringmember 126 to rotate therewith. Thus, blade assembly 128 may consist ofa connecting frame 132 supporting an earth cutting blade 134 which ismovable as to angle of attack by means of a hydraulic cylinder 136, suchstructure to be further described in greater detail.

H68. 3, 4 and depict elements of the B END mobile assembly 14 in greaterdetail. It should be understood that the A END mobile assembly 12 may beconstructed in identical manner. The tandem assembly 18b is actually acommercially available mechanical unit which enables four wheel drive oftandem arranged wheels, e.g. a separate type final drive utilizing atandem axle. Casings 140 and 142 of tandem assembly 18b each include aseparate sprocket and chain drive for each of the respective front andrear wheels 20b. The tandem assemblies include a transverse axle 144,and a pair of oppositely disposed clamping brackets 145 are weldedbeneath chassis 22b to provide secure engagement for support upontransverse axle 144. The tandem axle 144 receives drive rotation from astraight-through gear drive assembly 146 which is connected to receiverotational input through a coupling 148. The rotational input coupling148 is taken from the output of a suitable hydraulic motor 150, e.g. aSeries 27 Sundstrand hydraulic motor as driven from a suitable hydraulicpump 152, e.g. a Series 25 Sundstrand hydraulic pump. While specifichydraulic pump and motor equipment is identified, it should beunderstood that a great many combinations of differing power and typemight be utilized to provide the drive power.

Hydraulic pressure generated in hydraulic pump 152 is also utilized inconventional manner to drive various of the hydraulic control elementsdisposed about the motor-grader as sembly 10, as will be furtherdescribed. The hydraulic pump 152 is energized from diesel engine 24b asrotational engine output applied to a parallel array of flywheels 154 istransmitted on a plurality of V-belts 156 to a plural belt pulley 158which, in turn, applies rotational input to hydraulic pump 152.Hydraulic pump 152 working in concert with conventional reservoir means(not shown) provides pressure output from a coupling 160 for conductionto an input coupling 162 for energization of the hydraulic motor 150. Anadditional plu rality of flywheel pulleys 164 may be used to provide anadditional rotational output from engine 24b for connection to otherauxiliary pump means (not shown) which might be employed for poweringauxiliary implement control mechanisms and such, as will be furtherdescribed below.

A vertical pivot shaft 166 is rigidly secured through a floor plate 168of chassis 22b (see also FIG. 6), and into rigid connection on top ofgear box 146 such that it extends vertically from the center of tandemassembly 18b, i.e. straight up from the intersection of drive axle 144through gear drive 146. Pivot shaft 166 is inserted upward through apivot bearing 170 which is formed to have oppositely disposed yoke arms172 and 174 extending outward for steering connection as will bedescribed. The pivot bearing 170 is also formed to have two oppositelydisposed connecting tabs 176 and 178 (FIG. 5) and these serve to providea connection for tilt control hydraulics as will also be describedbelow.

The pivot bearing 170 is mounted on pivot shaft 166 by means of a timkenbearing 180 (FIG. 6) of conventional type interposed concentricallytherebetween to provide necessary ease of the relative movement. Thepivot bearing 170 is formed to have a flange 182 about its upper end,and a frame support bearing 184 having a bottom flange 186 is securelyaffixed thereon, the placement of support bearing 184 also serving toposition and retain the timken bearing 180.

The support bearing 184 provides a rotational support for the frame end78. A steel support rod 188 of suitable size and strength is securelyaffixed as by welding through the front plate 190 of end frame 78, andsuitable reinforcing such as lateral plate 192 is also provided. Variousheavy construction techniques may be utilized to assure a strong bondbetween rod 188 and frame end 78 since the outer end of rod 188 mustsupport the entire end of the main frame 16 upon mobile assembly 14. Theouter end of rod 188 is rotationally retained within support bearing 84in similar manner as that utilized for pivot shaft 166 within pivotbearing 170. That is, a timken bearing 194 is interposed within theannular space between support rod 188 and the inner surface of supportbearing 184 and a retaining plate 196 is secured over the end of supportbearing 184 in such manner as to assure secure positioning of timkenbearing 194.

Steering control is effected by means of hydraulic cylinders 198 and 200which are connected at pivot ends 202 and 204 to a connecting frame 206which is rigidly secured through transverse beam 208 to the chassis 22b.Hydraulic pistons 210 and 212 are connected to respective yoke arms 172and 174 of pivot bearing 170, and energization in concert of hydrauliccylinders 198 and 200 will provide rotation of yoke arms 172 and 174(pivot bearing 170) relative to the pivot shaft 166 which is alsosecured to chassis 22b of mobile assembly 14.

Tilt control of main frame 16 is effected by control of hydrauliccylinders 214 and 216. Hydraulic cylinders 214 and 216 are reachpivotally mounted by means of respective pivot pins 218 and 220 whichare affixed thereto and pivotally interconnected within bracket plates222 and 224 which are secured through suitable spacers 226 on frontplate 190 of the bifurcated frame end 78. Hydraulic cylinders 214 and216 extend respective pistons 228 and 230 downward into pivotalconnection with connecting tabs 176 and'178 as disposed on oppositesides of pivot bearing 170. Coordinated control of hydraulic cylinders214 and 216 effects tilting of frame end 78 and, therefore, main frame16 about the. longitudinal axis established by the bearing of supportrod 188 within support bearing 184.

Frame locking is provided by a hydraulic cylinder 232 which may beselectively actuated to extend its piston rod (not specifically shown)into a locking hole which is formed within a locking block 234. Lockingblock 234 consists merely of a block of steel with a hole therethroughand which is secured at a front center point of forward plate 190 of endframe 78. Hydraulic cylinder 232 is then supported in longitudinalrelationship by a mounting plate 236 suspended by a pair of supportplates 238 each rigidly secured above the support bearing 184. Theoperator can effect control of cylinder 232 to extend the piston intolocking block 234, this serving to maintain continuous positioning ofthe hydraulic locking cylinder 232 in vertical alignment, said verticalalignment assuring lateral horizontal positioning of frame end 78.

Referring now to FIG. 7, the main frame 16 is provided with uniqueadjustability through pivotal connection of end frames 78 and 80 to thecentral frame 38. The subframe 110 is secured from pivot assemblies 112and 116 from opposite ends of central frame 38. That is, a bearingsleeve 240 secured from a sleeve hanger 242 as rigidly affixed beneathtransverse member 114 (FIG. 2), a part of the main frame 38, is securedabout the bearing pin as supported by plates 246 and 248. Pivot assembly1 16 at the opposite end is similarly constructed and supported from theopposite end of main frame 38 with a hanger 250 supporting a bearingsleeve 252 for pivotal support about a bearing pin 254 as securedbetween vertical plates 256 and 258.

A plurality of adjustable ring support blocks 130 (FIG. 2) are disposedat approximately equal distances about the underside of subframe 110 tosupport the ring 126 moveably therearound. Each of support blocks isindividually adjustable for setting level and centering of the ring 126.A ring drive hydraulic motor 260 is suitably mounted to work into a wormgear 262 which transmits rotational force to a drive gear 264. Drivegear 264 is positioned in engagement with an inner, gear-toothed flange266 of ring 126 to transmit motion therethrough.

A pair of implement support plates 270 are rigidly affixed in paralleldisposition across opposite sides of ring 126. Referring to FIG. 7, eachof the implement support panels 270 has a similarly shaped and downwardextending panel 132 which serves to pivotally support an adjusting plate272 about a pivotal connection 274. A blade 134 is secured by a suitableform of connection 276 to said adjusting plate 272 for movementtherewith. Hydraulic cylinders 1'36, pivotally connected to ring 126,extend a piston 278 into pivotal connection with a lever mechanism 280which exerts positioning control on the blade 134. The hydraulicadjusting cylinder 136, as well as adjusting plate 272, connectingmechanism 276 and other related components are duplicated on each sideof the ringl26, i.e. as associated with each of implement support panels270.

in prototype equipment, the various control power functions about themotor-grader assembly have been effected by the use of hydraulicequipment; however, it should be understood that these functions can beperformed byaany of the conventional powering methods such aselectrical, pneumatic, mechanical, or any combination of such powercircuits. Control functions are readily regulated by the operator in themovable operating cab and, in addition to manual control, it is oftendesirable to enable automatic control of certain level and steeringfunctions so that the motor-grader assembly 10 can be controlled totallyor in pan from an external grade reference such as a string line. Suchmanual-automatic control functions as specifically directed to hydraulicequipmentation are more particularly set forth hereinafter.

- -As shown in FIG. 8, a frame level control 282 provides setting of theelevation and level of main frame assembly 16. Such height control iseffected by adjustment of the hydraulic cylinders and/or 94 (see alsoFIG. 1). A dual control assembly 284, situated in the operator's cab100, provides a first manual lever switch 286 for controlling A ENDelevation and a second manual lever control 288 for controlling 8 ENDheight.

A pair of hydraulic connections 288 and 290 are connected to hydrauliccylinder 94 and to a four-way valve 292. The hydraulic valve 292 is acommercially available four-way type which has a quiescent or lookcentral portion 294 as well as oppositely porting spool sections 296 and298. The valve 292 is then controlled by energization of one or theother of the end-mounted solenoids 300 and 302 which provide the properflow of hydraulic fluid to the hydraulic cylinder 294. Hydraulicconnections 304 and 306 are shown connected to a sump which may be anysuitable form of hydraulic pump and reservoir system compatible with theavailable power requirements and drive input energy.

Manual lever switch 286 provides A END control by energization ofelectrical leads 308 and 310 to actuate one or the other of solenoids300 and 302. Similarly, manual lever 288 provides B END actuation byenergization of respective ones of electrical connections 312 and 314 toactuate solenoids 316 and 318. These solenoids 316 and 318 provideopposite actuation of a four-way hydraulic valve 320 which has a centrallockup section 322 as well as oppositely flowing port sections 324 and326. Hydraulic lines 328 and 330 connect. between hydraulic cylinder 90and four-way valve 320, with hydraulic lines 332 and 334 leading to asuitable hydraulic pressure sump.

The schematic representation of FIG. 9 illustrates a control system 336which controls the cross slope of the subframe and whatever the workingimplement suspended therebeneath. The subframe l 10 has its cross slopeadjusted in accordance with the actuation of hydraulic cylinders 118 and120 which are oppositely connected in parallel to hydraulic lines 338and 340 from a four-way valve 342 thereby to effect reciprocal cylinderaction. Four-way valve 342 is connected to source hydraulic lines 344and 346, and valve 342 consists of a lockup section 348 as well asopposite porting sections 350 and 352 which are positioned by oppositelyactuating solenoids 354 and 356, respectively.

Solenoids 354 and 356 are controlled via electrical connections 358 and360 from a suitable cross slope selector 362 which, in turn, receivesinput from a manual cross slope control 364 and. an automatic crossslope control 366. The manual cross slope control 364 may be located inthe operating cab 100, while the automatic cross slope control 366refers to control energization originating from suitable control sensorswhich are responsive to an external reference, as will be furtherdescribed below. The automatic cross slope control 366 may be such as agravity responsive switch with suitable output which is adjustable inrelation to a pendulum or such.

Referring now to FIG. 10, an automatic-manual steering system 370includes A END steering assembly 372 and a B END steering assembly 374.Manual steering is carried out by means of a steering control unit 376,the subject matter of FIG. 11 as will be further described, withsteering end selection being made through a manual steering end selectorswitch 378. Automatic steering in response to sensing of an externalreference is carried out in response to an A END steering control 380 ora 8 END steering control 382 as selected by a steering selector 384 forinput via leads 386 and 388 to each of an A END four-way valve 388 and aB END four-way valve 390.

Manual steering is carried out by steering control unit 376 which iscontrolled to steer one end or the other in response to actuation ofmanual steering end selector 378. Thus, in the case where the A ENDassembly 372 is to be steered, hydraulic fluid output in one directionorthe other is present on hydraulic lines 392 and 394 to a double-endedhydraulic cylinder 396. The hydraulic cylinder 396 has one end 398pivotally connected to a valve spool 400 of a heavy duty hydraulic valve402, e.g. a 30 gallon four-way valve. The hydraulic valve 402 isenergized by hydraulic pressure present on hydraulic lines 404 and 406from a suitable sump, and valve output is directed through hydrauliclines 408 and 410 which are applied in opposite, parallel connectionthrough respective steering cylinders 198a and 2001:. Thus, applicationsof pressure differential, as between hydraulic lines 408 and 410,results in reciprocal action of hydraulic cylinder pistons 212a and 2100to effect pivoting of the steering yoke 1720-1740 which is in rigidaffixure to the main frame 16.

Steering of the B END steering assembly 374 is effected by applicationof a hydraulic fluid differential between hydraulic lines 412 and 414 toa double-ended hydraulic cylinder 416. The hydraulic cylinder 416 drivesa reciprocal valve spool 418 of a heavy duty hydraulic valve 420 in thesame manner as described for the A END assembly. That is, hydraulicsource input is via lines 422 and 424 with regulating fluid output alonghydraulic lines 426 and 428 to each of the hydraulic steering cylinders430 and 432. The fluid input to hydraulic cylinders 430 and 432 is inparallel but opposite orientation to effect reciprocal movement ofrespective piston rods 210 and 212 thereby to effect steering movement.

Automatic steering, as might be effected from suitable control sensorsoperating in response to an external reference, would originate as anelectrical control signal in the form of a switch closure via leads 386through 389 to energize predetermined valve solenoids. Thus, anenergizing voltage on lead 386 to valve solenoid 438 changes four-wayvalve 388 from its center or lockup position 440 to spool position 442which directs hydraulic fluid from pressure source lines 444 and 446through respective hydraulic lines 408 and 410 to cause reciprocalenergization of hydraulic cylinders 198a and 200a. Energization via lead387 energizes solenoid valve 448 such that valve spool section 450effects an opposite hydraulic pressure differential as between hydrauliclines 408 and 410. Upon deenergization of either of valve solenoids 438or 448, the valve spool is allowed to return to its lockup position orspool section 440.

Automatic steering of the B END steering assembly is effected in similarmanner. That is, electrical energization of either of leads 388 or 389actuates respective valve solenoids 452 and 454. Actuation of solenoidvalve 452 moves the valve spool from its lockup position 456 to theposition where spool section 458 directs hydraulic fluid flow fromsource lines 460 and 462 through respective supply lines 426 and 428.Alternate energization of the valve solenoid 454 places spool section464 in operation to reverse the pressure differential as betweenhydraulic lines 426 and 428, this effecting an opposite reciprocaleffect as between the steering cylinders 430 and 432.

The steering control unit 376 is shown in greater detail in FIG. 11which includes various valve interconnections for responding to themanually operated steering wheel 470. Steering wheel 470 is connected bymeans of a suitable mechanical linkage 472 to operate an orbitrolmechanism 474. The orbitrol 474 is a well-known type of hydraulicproportioning pump which varies the direction and force of hydraulicflow as between pressure lines 476 and 478. The lines 476 and 478 areconnected to supply fluid pressure input to respective four-wayhydraulic valves 480 and 482 with pressure return proceeding viahydraulic lines 484 and 486 to a fluid reservoir 488. Pressure relief isafforded by a common fluid connection 490 through oppositely orientedcheck valves 492 and 494 with return to the respective input pressurelines 476 and 478.

Electrical input from manual steering end selector 478 (FIG. 10) isprovided by signal input on leads 496 and 498. Thus, input on lead 496energizes solenoid valves 500 and 502 to bring respective valve spoolsections 504 and 506 into function, this enabling A END steering controlof the A END cylinder 396. Energization on lead 498 actuates valvesolenoids 508 and 510 to move valve spool sections 512 and 514 in theproper flow position such that the B END cylinder 416 is energizable inresponse to the adjustment of orbitrol 474 for manually steering themotor-grader assembly. The center spool positions 516 and 518 of therespective four-way valves 480 and 482 merely provide pressure balancingporting.

Referring now to FIG. 12, a main frame tilt control assembly 520exercises selected control of lateral tilting of the A END or the B ENDor both ends simultaneously of the main frame relative to the respectiveA END and B END mobile assemblies l2 and 14. As shown, the B END is inthe unlocked position as B END unlock control 522 provides energizingvoltage via lead 524 to energize valve solenoid 526 such that a four-wayvalve 528 is actuated to energize hydraulic locking cylinder 232 suchthat its locking piston 530 is withdrawn out of engagement with lockingblock 324. Alternately, the A END unlock 532 will be deenergized suchthat valve solenoid 534 does not actuate a four-way valve 536. In thisposition, the valve 536 actuates locking cylinder 323a such that alocking pin 530a is forced into locking engagement within locking block2340.

With the A END unlock 532 deenergized to cause locking of the frame AEND, a B END tilt control 538 may then be controlled by energizationalong either of electrical ends 540 or 542 to effect frame tiltingrelative to the B END mobile assembly. Energization of lead 540energizes valve solenoid 544 such that a four-way valve 546 is actuatedfrom its lockup spool section 548 to a spool section 550 to place apressure differential between hydraulic lines 552 and 554.

When the A END unlock 532 is energized to withdraw the locking pin 5300the hydraulic tilt cylinders 216a and 2140 may be energized to effectlateral tilting of main frame. Thus, an A END tilt control 560 may beselectively actuated to energize one or the other of leads 562 or 564 toenergize respective solenoids 566 or 568. A hydraulic valve 570 isnormally positioned with the lockup spool section 572 in circuit withpressure source lines 574 and 576 and the hydraulic circuit lines 578and 580. Pressure lines 578 and 580 are then connected in parallel toeach of hydraulic tilt cylinders 216a and 214a to effect reciprocalpiston action upon energization of either of relays 566 or 568.Energization of relay 566 brings valve spool section 582 into function,while energization of relay 568 will bring the opposite valve spoolsection 584 to cause reverse pressure application.

A hydraulic override function is provided at each frame end throughoperation of check valves 586, 588, 590 and 592. Thus, not until the BEND is unlocked with energization of valve solenoid 526 can thehydraulic tilt cylinders 216 and 214 be actuated. 1n the unlockattitude, valve spool section 528 applies pressure via hydraulic line594 to open each of the respective check valves 586 and 588 such thatthey will then allow hydraulic pressure application as present on eitherof hydraulic lines 552 and 554 to the tilt control cylinders 214 and216. Similarly, check valves 590 and 592 are open with application ofpressure on hydraulic line 596 (opposite from that shown) to allowhydraulic actuation of tilt cylinders 214a and 216a.

Referring now to FIG. 13, motor-grader assembly 10 carries a suitabletracer bar 600 suspended in outrigged position as carried by supportarms 119 and 121 and respective telescoping rods 123 and 125. Supportarms 119 and 121 are each welded to opposite segments of subframe toextend laterally outboard, while telescoping rods 123 and 125 areadjustably held within support arms 119 and 121. Telescoping rods 123and 125 may be extended outward to any length as desired. A pair ofpivotal brackets 602 and 604 serve to secure the sensor rods 600 on theends of respective telescoping rods 123 and 125. The brackets 602 and604 should be a suitable pivot assembly since it will quite often berequired that telescoping rods 123 and 125 extend outward differentdistances. Such will be the case when motor-grader assembly 10 isoperated along an external reference or string line 606 with main frame16 canted relative to the A END and B END mobile assemblies 12 and 14.It should also be understood that telescoping rods can be readily fittedto extend outboard in the other direction, from the opposite ends ofsupport arms 119 and 120, as exigencies demand.

A bracket 608 and support 610 aid in the automatic steering function bycarrying a control sensor box 612 having a sensor rod 614 which isguided relative to string line 606. Automatic steering function at theopposite end is carried out by bracket 616, support arm 618, control box620 and sensor rod 622. The lengthwise placement of control sensor boxes612 and 620 may also be varied for differing applications. Thus, sensor2 boxes 612 and 620 may be aligned with the leading and trailing edgesof the furthest displaced (lengthwise) wheels of respective mobileassemblies 12 and l4 as is shown in FIG. 13.

Automatic elevation sensing indications are also derived from stringline 606 by means of brackets 624 and 626 which support additionalcontrol assemblies. Bracket 624 supports a control sensor box 626 and acounterweighted sensing rod 628 which travels along string line 606.Similarly, bracket 626 carries a control sensor box 632 having aweighted sensor rod 634. The control sensor boxes 612, 620, 628 and 632may all be a similar type such as is disclosed in a copending patentapplication entitled Line Tracer Control Device,38 Ser. No. 683,256,filed Nov. 15, 1967 in the name of Steele et al., now Pat. No. 3,514,630which is the property of the common assignee. Such control sensor boxprovides an electrical output in response to sensing variations relativeto string line 606, such electrical signals being conducted back toappropriate control assemblies on the structure of motor-grader assembly10.

The block diagram of FIG. 14 illustrates the interconnection of thevarious sensing and control components. Thus, output from A END steeringsensor 620 is applied to steering selector 384 which may be a main panelcontrol located in the operating cab 100. In the automatic attitude, AEND steering output from line 640 is applied via line 642 to causeproper function of hydraulic valve 388 such that steering cylinders 198aand 2000 are driven to effect a steering correction of the A END mobileassembly 12. Similarly, output from B END steering sensor 612 isconducted via lines 644 through steering selector 384 to a control lead646 which actuates hydraulic valve 390 to effect steering actuation ofthe B END steering cylinder 198 and 200. Manual steering control frommanual control unit 376 is an override control controlling selected onesof hydraulic valves 402 and/or 420. as shown more clearly in FIGS. 10and 11.

Automatic elevation sensing takes place in similar manner in response tosensor control boxes, i.e. A END elevation sensor 632 and B ENDelevation sensor 628. The respective outputs are applied via leads 648and 650 for circuit selection in selector 299. Selected outputs viacontrol leads 652'and 654 are applied to respective hydraulic valves,292and/or 320 to effect variation of height control cylinders 94 and 90.

It is also contemplated that cross slope control be carried outautomatically by a suitable form of transversely oriented sensor whichprovides zero or no output indication relative to' a preset elevationvalue. Thus, a suitable transverse level sensing mechanism may provide acontrol output for use in either the cross slope circuitry (FIG. 9) orthe main frame tilt control circuitry and hydraulics (FIG. 12) or both.Suchcontrol output could be applied to effect automatic following ofsupport structure which holds blade 134 at its cutting angle.

OPERATION The motor-grader assembly 10 is capable of operation in eitherlongitudinal direction under control of either an operator or anassociated external reference such as a string line.

assembly 10 and in parallel disposition to main frame 16. It

should be understood however that sensor rod 600 can be aligned at anyangular relationship relative to main frame 16, depending upon the angleof attack of the motor-grader assembly' in performing its earth-workingundertaking.

1 Referring also to FIG. 10, automatic steering is carried out inresponse to A END steering control 380 and B END steering control 382operating through steering selector 384. That is, more particularly,electrical outputs from A END steering sensor 620 and B END steeringsensor 612 (Fig. 14) as applied for selective actuation of hydraulicvalves 388 and 390. Thus, for A END steering, a sensed electrical outputfrom A END automatic steering control 380 is conducted via one or theother leads 386 and 387, depending upon the direction of turning, toactivate the associated valve solenoid 438 or 448 such that hydraulicvalve 388 provides the requisite pressure direction through steeringcylinders 198a and 200a.

Manual steering is effected in a different manner utilizing overridingpower application with the orbitrol and steering wheel structure of FIG.11. In this case, steering wheel 470 is manipulated to vary the orbitrolpump 474 to operate the proper one of'A END or B END hydraulic valves480 or 482. The valves 480 and 482, in turn, serve to energizerespective drive cylinders 396 and 416 to position the hydraulic valvespools within respective hydraulic cylinders 402 and 420 (FIG. 10).Valves 402 and 420 are heavy duty hydraulic valves which allow manualsteering as an override function with continual correction being appliedfrom an automatic steering source which may actuate the auxiliarysteering cor- 40 rection hydraulic valves 388 and 390, (see also FIG.10).

Referring to FIGS. 8 and 14, elevation control is carried outautomatically in response to A END elevation sensor 632 and B ENDelevation sensor 628 as applied to the selector 299. Elevation controlsignals are then conducted via leads 652 and 654 to energize one or bothof hydraulic valves 292 and 320 to activate their respective heightcontrol cylinders 294 and 290 located at each end of the main frame 16.Selector 299 also allows use of manual adjustment control 284 whichprovides parallel control of hydraulic valves 292 and 320.

It should be understood that various other schemes, both automatic andmanual, may be employed in controlling a motor-grader constructed inaccordance with the invention. Automatic controlmeasures may includevarious other external references in addition to the conventional stringline practices, such references being delineated by such as lighteffects, relative gravity effects, surface or slab sensing, etc. Also,while the motor-grader assembly 10 is shown as carrying a bladeimplement 134, it is contemplated that various attachment implementssuch as ripping attachments, trimmebspreader attachments, excavatorassemblies, etc. may be carried beneath the main frame inoperativealignment to carry out the earthworking function in response to eithermanual or automatic control.

The foregoing discloses a novel earth-working machinery controlsystemwhich is particularly applicable to double-articulatedmotor-grader assemblies, machines which enable greater work efficiencyper time expenditure. Such motorgrader assemblies have the additionaladvantages of being rreversible in operation such that various turningaround maneuvers areeliminated and this serves to cut down greatly onjob time. The control systems as disclosed herein offer particularadvantages in steering and elevation control of such double-endedmachines, elevation control being effected such that an entire-midframeassembly is variable both as to elevation and level relative to theearth or other selected reference, and automaticamanual steering can beeffected even from an offset or canted midframe position, as may berequired in particular earth-working situations.

Changes may be made in combination and arrangement of elements asheretofore set forth in the specification and shown in the drawings; itbeing understood that changes may be made in the embodiments disclosedwithout departing from the spirit and scope of the invention.

What is claimed is:

l. earth-working apparatus, comprising:

first mobile means including a drive power source pivotally aflixedabout a transverse axis to a tandem wheel mobile support structure;

second mobile means including a drive power source pivotally affixedabout a transverse axis to a tandem wheel mobile support structure; mainframe means of generally elongated form consisting of a central frameportion having opposite ends pivotally affixed along atransversehorizontal axis to first and second end frame portions and having eachof first and second end frame portions universally pivotally affixed formovement about either vertical or longitudinal axes as connected torespective first and second mobile means at a generally central positionrelative to the respective tandem wheels; subframe means supportedbeneath said central frame portion and supported pivotally about alongitudinal axis;

implement means adjustably supported from a circle assembly securedbeneath said subframe means in an earthworking position;

control means including control elements connected to said main framemeans for selectively adjusting the height and level of the centralframe portion of the main frame means by independently raising andlowering said main frame means central frame portion relative to saidfirst and second end frame portions;

reference means external to said apparatus denoting a predeterminedposition in space; and

sensing means extending laterally from said central frame portion andresponsive to relative changes of said reference means to generate acorrection signal for input to said control means to effect saidselective adjustment of height and level of the central frame portion ofthe main frame means.

2. Earth-working apparatus as set forth in claim 1 wherein said controlmeans comprises:

first power means affixed between said first end frame means and saidfirst end of the central frame portion which power means is elongatablyadjustable; second power means affixed between said second end framemeans and said second end of the central frame portion which secondpower means is elongatably adjustable; and

first and second actuation means connected to respective power meanswhich are selectively controllable to effect adjustment of one or bothof said first and second power means to vary the height and level ofsaid central frame portion. 3. Earth-working apparatus as set forth inclaim 1 which is further characterized to include: 1

second control means including connected control elements connectedbetween said main frame means and said first mobile means to selectivelyadjust the longitudinal angle of the main frame means relative to saidfirst mobile means; and

third control means including connected control elements connectedbetween said main frame means and said first mobile means to selectivelyadjust the longitudinal angle of the main frame means relative to saidsecond mobile means.

4. Earth-working apparatus as set forth in claim 3 wherein said secondcontrol means comprises:

first power means affixed between said first end frame means and saidfirst end of the central frame portion which power means is elongatablyadjustable;

second power means affixed between said second end frame 5 means andsaid second end of the central frame portion which second power means iselongatably adjustable; and

first and second actuation means connected to respective power meanswhich are selectively controllable to effect 1 o adjustment of one orboth of said first and second power means to vary the height and levelof said central frame portion. 5. Earth-working apparatus as set forthin claim 4 each of said actuation means comprises: 1 a hydraulic powersource;

hydraulic valve means connected to said hydraulic power source andoperable to actuate said respective first or second power means; andsteering control means at an operating position which is manuallyoperable to control the actuation of said hydraulic valve means. 6.Earth-working apparatus as set forth in claim 2 wherein each of saidfirst and second power means comprises:

a hydraulic cylinder means. 7. Earth-working apparatus as set forth inclaim 4 wherein each of said first and second power means comprises:

a hydraulic cylinder means. 8. Earth-working apparatus as set forth inclaim 1 which is further characterized to include:

first power means afiixed between said first mobile means and extendinggenerally transversely and downward for connection with said first endof the main frame means which power means is elongatably adjustable;second power means affixed between said second mobile means andextending generally transversely and downward for connection with saidsecond end of the main frame means, which second means is elongatablyadjustable; and first and second actuation means connected to respectivepower means which are selectively controllable to effect adjustment ofone or both of said first and second power means to vary the tilt angleof said main frame means transversely about its longitudinal axis andrelative to each of their respective first and second mobile means. 9.Earth-working apparatus as set forth in claim 8 which is furthercharacterized to include:

first locking means affixed to said first mobile means for selectiveactuation to lock said first mobile means to said main frame means inrigid affixure; second locking means affixed to said second mobile meansand selectively actuatable to lock said second mobile means to saidsecond end of said main frame means in rigid affixure; and first andsecond actuation means connected to respective locking means which areselectively controllable to actuate said first and second locking means.10. Earth-working apparatus as set forth in claim 8 wherein each of saidfirst and second power means comprises:

wherein a pair of hydraulic cylinders pivotally affixed to oppositesides of said respective first and second ends of the main frame meansand having respective opposite ends pivotally affixed to said respectivemobile means at a laterally outboard position.

11. Earth-working apparatus as set forth in claim 9 wherein each of saidfirst and second locking means comprises;

locking pin receiving means mounted on each respective end of the mainframe means; and hydraulic locking means including a locking pin, saidlocking means being mounted on each of the respective mobile means to beactuated to extend the respective locking pins into said pin receivingmeans. 12. Earth-working apparatus as set forth in claim 1 wherein 75each of said second sensing means comprises:

selectively actuated in response to said first and second steeringoutputs to adjust the directional angle of the main frame means.

14. Earth-working apparatus as set forth in claim 13 which is furthercharacterized to include:

manual steering control means at an operating position providing firstand second control outputs for selective adjustment of said secondcontrol means.

1. EARTH-WORKING APPARATUS, COMPRISING: FIRST MOBILE MEANS INCLUDING ADRIVE POWER SOURCE PIVOTALLY AFFIXED ABOUT A TRANSVERSE AXIS TO A TANDEMWHEEL MOBILE SUPPORT STRUCTURE; SECOND MOBILE MEANS INCLUDING A DRIVEPOWER SOURCE PIVOTALLY AFFIXED ABOUT A TRANSVERSE AXIS TO A TANDEM WHEELMOBILE SUPPORT STRUCTURE; MAIN FRAME MEANS OF GENERALLY ELONGATED FORMCONSISTING OF A CENTRAL FRAME PORTION HAVING OPPOSITE ENDS PIVOTALLYAFFIXED ALONG A TRANSVERSE HORIZONTAL AXIS TO FIRST AND SECOND END FRAMEPORTIONS AND HAVING EACH OF FIRST AND SECOND END FRAME PORTIONSUNIVERSALLY PIVOTALLY AFFIXED FOR MOVEMENT ABOUT EITHER VERTICAL ORLONGITUDINAL AXES AS CONNECTED TO RESPECTIVE FIRST AND SECOND MOBILEMEANS AT A GENERALLY CENTRAL POSITION RELATIVE TO THE RESPECTIVE TANDEMWHEELS; SUBFRAME MEANS SUPPORTED BENEATH SAID CENTRAL FRAME PORTION ANDSUPPORTED PIVOTALLY ABOUT A LONGITUDINAL AXIS; IMPLEMENT MEANSADJUSTABLY SUPPORTED FROM A CIRCLE ASSEMBLY SECURED BENEATH SAIDSUBFRAME MEANS IN AN EARTH-WORKING POSITION; CONTROL MEANS INCLUDINGCONTROL ELEMENTS CONNECTED TO SAID MAIN FRAME MEANS FOR SELECTIVELYADJUSTING THE HEIGHT AND LEVEL OF THE CENTRAL FRAME PORTION OF THE MAINFRAME MEANS BY INDEPENDENTLY RAISING AND LOWERING SAID MAIN FRAME MEANSCENTRAL FRAME PORTION RELATIVE TO SAID FIRST AND SECOND END FRAMEPORTIONS; REFERENCE MEANS EXTERNAL TO SAID APPARATUS DENOTING APREDETERMINED POSITION IN SPACE; AND SENSING MEANS EXTENDING LATERALLYFROM SAID CENTRAL FRAME PORTION AND RESPONSIVE TO RELATIVE CHANGES OFSAID REFERENCE MEANS TO GENERATE A CORRECTION SIGNAL FOR INPUT TO SAIDCONTROL MEANS TO EFFECT SAID SELECTIVE ADJUSTMENT OF HEIGHT AND LEVEL OFTHE CENTRAL FRAME PORTION OF THE MAIN FRAME MEANS.
 2. Earth-workingapparatus as set forth in claim 1 wherein said control means comprises:first power means affixed between said first end frame means and saidfirst end of the central frame portion which power means is elongatablyadjustable; second power means affixed between said second end framemeans and said second end of the central frame portion which secondpower means is elongatably adjustable; and first and second actuationmeans connected to respective power means which are selectivelycontrollable to effect adjustment of one or both of said first andsecond power means to vary the height and level of said central frameportion.
 3. Earth-working apparatus as set forth in claim 1 which isfurther characterized to include: second control means includingconnected control elements connected between said main frame means andsaid first mobile means to selectively adjust the longitudinal angle ofthe main frame means relative to said first mobile means; and thirdcontrol means including connected control elements connected betweensaid main frame means and said first mobile means to selectively adjustthe longitudinal angle of the main frame means relative to said secondmobile means.
 4. Earth-working apparatus as set forth in claim 3 whereinsaid second control means comprises: first power means affixed betweensaid first end frame means and said first end of the central frameportion which power means is elongatably adjustable; second power meansaffixed between said second end frame means and said second end of thecentral frame portion which second power means is elongatablyadjustable; and first and second actuation means connected to respectivepower means which are selectively controllable to effect adjustment ofone or both of said first and second power means to vary the height andlevel of said central frame portion.
 5. Earth-working apparatus as setforth in claim 4 wherein each of said actuation means comprises: ahydraulic power source; hydraulic valve means connected to saidhydraulic power source and operable to actuate said reSpective first orsecond power means; and steering control means at an operating positionwhich is manually operable to control the actuation of said hydraulicvalve means.
 6. Earth-working apparatus as set forth in claim 2 whereineach of said first and second power means comprises: a hydrauliccylinder means.
 7. Earth-working apparatus as set forth in claim 4wherein each of said first and second power means comprises: a hydrauliccylinder means.
 8. Earth-working apparatus as set forth in claim 1 whichis further characterized to include: first power means affixed betweensaid first mobile means and extending generally transversely anddownward for connection with said first end of the main frame meanswhich power means is elongatably adjustable; second power means affixedbetween said second mobile means and extending generally transverselyand downward for connection with said second end of the main framemeans, which second means is elongatably adjustable; and first andsecond actuation means connected to respective power means which areselectively controllable to effect adjustment of one or both of saidfirst and second power means to vary the tilt angle of said main framemeans transversely about its longitudinal axis and relative to each oftheir respective first and second mobile means.
 9. Earth-workingapparatus as set forth in claim 8 which is further characterized toinclude: first locking means affixed to said first mobile means forselective actuation to lock said first mobile means to said main framemeans in rigid affixure; second locking means affixed to said secondmobile means and selectively actuatable to lock said second mobile meansto said second end of said main frame means in rigid affixure; and firstand second actuation means connected to respective locking means whichare selectively controllable to actuate said first and second lockingmeans.
 10. Earth-working apparatus as set forth in claim 8 wherein eachof said first and second power means comprises: a pair of hydrauliccylinders pivotally affixed to opposite sides of said respective firstand second ends of the main frame means and having respective oppositeends pivotally affixed to said respective mobile means at a laterallyoutboard position.
 11. Earth-working apparatus as set forth in claim 9wherein each of said first and second locking means comprises: lockingpin receiving means mounted on each respective end of the main framemeans; and hydraulic locking means including a locking pin, said lockingmeans being mounted on each of the respective mobile means to beactuated to extend the respective locking pins into said pin receivingmeans.
 12. Earth-working apparatus as set forth in claim 1 wherein eachof said second sensing means comprises: electrical switch means whichprovides first and second switch closures for respective oppositevariations in relative position from said reference means. 13.Earth-working apparatus as set forth in claim 3 wherein said secondcontrol means comprises: steering selector means located at an operatingposition on said main frame for receiving each of said first and secondsensing outputs from said second control means; and hydraulic meansconnected to said main frame means and selectively actuated in responseto said first and second steering outputs to adjust the directionalangle of the main frame means.
 14. Earth-working apparatus as set forthin claim 13 which is further characterized to include: manual steeringcontrol means at an operating position providing first and secondcontrol outputs for selective adjustment of said second control means.